1. Field of the Invention
The present invention relates to a manufacturing method for laminated ceramic electronic components used as, for example, inductors, LC components, and feedthrough capacitors, and to a laminated ceramic electronic component, and more specifically, the present invention relates to a manufacturing method for the laminated ceramic electronic component wherein the process of forming the inner electrode is improved and inner electrodes of increased thickness are provided, and relates to a laminated ceramic electronic component produced thereby.
2. Description of the Related Art
Laminated inductors using sintered materials obtained by integrally firing metals and ceramics are known. In the manufacture of a laminated inductor, first, an inner electrode paste for forming a coil conductor is printed on a ceramic green sheet. A through hole for electrically connecting the upper and lower inner electrodes is provided in the ceramic green sheet. Plural layers of the green sheets are laminated together and the obtained laminate is pressed in the direction of the thickness. Thereafter, the laminate is fired to produce a ceramic sintered body, and a pair of outer electrodes, which is electrically connected to the coil conductor, is provided on the outer surface of the ceramic sintered body.
In the aforementioned laminated inductors, the number of windings can be increased by increasing the number of laminated layers of the ceramic green sheet, and a large inductance can thereby be obtained.
In this method, however, when printing the inner electrode paste to form the coil conductor on the ceramic green sheet to accompany the increased number of laminated layers of the ceramic green sheet, at the time when the aforementioned laminate is obtained, the height difference between the portion where the inner electrode paste exists and the portion where the paste does not exist, greatly increases. Therefore, when the laminate is pressed in the direction of the thickness before firing, distortion occurs. Furthermore, after firing, an interlayer peeling phenomenon, called xe2x80x9cdelaminationxe2x80x9d occurs due to the aforementioned distortion.
On the other hand, in the aforementioned laminated inductor, to reduce the direct current resistance, it is necessary to increase the thickness of the coil conductor or to increase the width of the coil conductor. In this method, however, when printing the inner electrode paste on the ceramic green sheet to form the inner electrode, for example, the coil conductor, it is difficult to form a thick inner electrode by a single printing process step.
Even if the printing of the inner electrode paste is repeated several times and an inner electrode of large thickness is formed, when the laminate is pressed in the direction of the thickness, the aforementioned interlayer peeling phenomenon in the obtained ceramic sintered body occurs.
Furthermore, where the width of the coil conductor is increased to reduce the direct current resistance, the inductance is substantially lowered.
Not only in laminated inductors, but also in laminated ceramic electronic components, such as monolithic ceramic capacitors, similar problems occur. That is, when the number of laminated layers of the inner electrode is increased, the distortion due to the adhesion by pressing increases, and the aforementioned delamination occurs. When the thickness of the inner electrode is increased to lower the direct current resistance, the aforementioned delamination occurs even more often.
To overcome the above-described problems with the prior art, preferred embodiments of the present invention provide a manufacturing method for a laminated ceramic electronic component and a laminated ceramic electronic component, wherein the thickness of the inner electrode is easily increased, and even when the number of laminated layers of the inner electrode is increased, the aforementioned delamination does not occur.
Preferred embodiments of the present invention further provide a manufacturing method for a laminated inductor, wherein the thickness of the coil conductor defining the inner electrode is easily increased, and even when the number of laminated layers of the inner electrode is increased, delamination does not occur, and furthermore, a greatly increased inductance is easily obtained.
According to a first preferred embodiment of the present invention, a manufacturing method for the laminated ceramic electronic component includes a process wherein a ceramic paste is printed on a carrier film except for a portion on which an inner electrode is provided, a process wherein an inner electrode paste is printed on the portion of the aforementioned carrier film, on which the inner electrode is provided, such that a green sheet defined by the ceramic paste layer and the inner electrode paste layer is produced, a process wherein the green sheet is laminated by repeating the process in which a laminate of the green sheet and the carrier film is adhered by pressing to another green sheet on a lamination stage, and thereafter the carrier film is peeled off to yield a ceramic laminate, and a process wherein the aforementioned ceramic laminate is fired to obtain a ceramic sintered body. Herein, the xe2x80x9canother green sheetxe2x80x9d may or may not include an inner electrode paste layer.
In a specific aspect of the manufacturing method for the laminated ceramic electronic component according to the first preferred embodiment, the aforementioned printing process for the ceramic paste is executed after the aforementioned printing process for the inner electrode paste.
In another specific aspect of the manufacturing method for the laminated ceramic electronic component according to the first preferred embodiment, the aforementioned printing process for the ceramic paste is executed before the aforementioned printing process for the inner electrode paste.
In another specific aspect of the manufacturing method for the laminated ceramic electronic component according to the first preferred embodiment, a process, wherein plural layers of the aforementioned green sheet, on which inner electrode paste layers having substantially the same shape are provided, and which are supported by a carrier film, are laminated and adhered by pressing to another green sheet on the lamination stage, and thereafter the carrier film is peeled off, and this is repeated a plurality of times to form an inner electrode having a thickness matching the entirety of laminated plural inner electrode paste layers.
According to the second preferred embodiment of the present invention, a manufacturing method for the laminated ceramic electronic component includes a process wherein first and the second composite sheets are prepared and supported on a carrier film, and in which an inner electrode paste layer and a ceramic green sheet layer are formed such that the inner electrode paste layer penetrates both primary surfaces of the ceramic green sheet layer; a process wherein the first composite sheet is laminated and adhered by pressing to another green sheet on the lamination stage, and thereafter the carrier film is peeled off; a process wherein the second composite sheet is laminated and adhered by pressing to the first composite sheet, and thereafter the carrier film laminated on the second composite sheet is peeled off, and thereby an inner electrode is formed in which the inner electrode paste layers of the first and the second composite sheets are laminated; and a process wherein the laminate obtained by the aforementioned laminating process is sintered to obtain a ceramic sintered body.
According to a third preferred embodiment of the present invention, a manufacturing method for the laminated ceramic electronic component includes a process wherein a plurality of layers of electrode green sheet are prepared which are supported on a carrier film, and in which a ceramic layer is provided surrounding an inner electrode defining an inductance such that the inner electrode defining the inductance penetrates the top surface and the bottom surface of the ceramic layer; a process wherein at least a layer of a connection electrode green sheet is provided which is supported on a carrier film, and in which a ceramic layer is provided surrounding the connection electrode such that the connection electrode is exposed at the top surface and the bottom surface of the ceramic layer; a process wherein the electrode green sheet and the connection electrode green sheet are laminated to produce a laminate while being peeled from the carrier film such that the inner electrode defining the inductor is electrically connected via the aforementioned connection electrode to define a coil; and a process wherein the aforementioned laminate is fired to obtain a ceramic sintered body.
In a specific aspect of the manufacturing method for the laminated ceramic electronic component according to the third preferred embodiment, a plurality of layers of the aforementioned electrode sheet, on which the inner electrodes which define an inductor in substantially the same shape are provided, are laminated to define an inner electrode over a plurality of layers.
In another specific aspect of the manufacturing method for the laminated ceramic electronic component according to the third preferred embodiment, in the aforementioned laminating process, the aforementioned carrier film is peeled off after adhering the electrode green sheet and the connection electrode green sheet by pressing.
The fourth preferred embodiment of the present invention is a manufacturing method for the laminated ceramic electronic component, including a process wherein an electrode green sheet is prepared, which is supported on a carrier film, and in which a ceramic layer is provided surrounding an inner electrode to define an inductor such that the inner electrode defining the inductor is exposed at the top surface and the bottom surface of the ceramic layer; a process wherein the aforementioned green sheet is laminated to obtain a laminate, while peeling the carrier film such that the inner electrodes are electrically connected to each other to define a coil conductor; and a process wherein the aforementioned laminate is fired to obtain a ceramic sintered body.
In the specific aspect of the manufacturing method of the laminated ceramic electronic component according to the fourth preferred embodiment, the aforementioned carrier film is peeled off after adhering the aforementioned electrode green sheet by pressing.
In another specific aspect of the manufacturing method for the laminated ceramic electronic component according to the fourth preferred embodiment, a plurality of layers of the electrode green sheet, on which the inner electrodes which define an inductor in substantially the same pattern are provided, are directly laminated to define an inner electrode over the plurality of layers.
A manufacturing method for the laminated ceramic electronic component according to a fifth preferred of the present invention includes a process wherein a plurality of layers of electrode green sheet to define an inductor are prepared, which are supported on a carrier film, and in which a ceramic layer is provided surrounding an inner electrode to define the inductor such that the inner electrode to define the inductor penetrates the top surface and the bottom surface of the ceramic layer; a process wherein a plurality of layers of electrode green sheet defining a capacitor are prepared, which are supported on a carrier film, and in which a ceramic layer is provided surrounding an inner electrode defining the capacitor such that the inner electrode defining the capacitor penetrates the top surface and the bottom surface of the ceramic layer; a process wherein a plain ceramic green sheet supported on a carrier film is prepared; and a process including the first laminating process, in which the aforementioned electrode green sheet defining the inductor is laminated while being peeled from the carrier film such that the plurality of layers of inner electrode defining the inductor are electrically connected in the direction of the lamination to define a coil, and the second laminating process, in which the aforementioned electrode green sheet defining the capacitor and the aforementioned plain green sheet are laminated while being peeled from the carrier film such that the plurality of layers of electrode green sheet defining the capacitor are laminated interposing the plain green sheet, wherein the laminate, obtained by executing the aforementioned first and second laminating processes in order or in reverse order, is fired to yield a ceramic sintered body.
According to the fifth preferred embodiment, the ceramic sintered body is obtained by sintering the laminate obtained by executing the aforementioned first and second laminating processes in order or in reverse order, and in the ceramic sintered body, an inductance unit including the coil defined by connecting the inner electrode defining the inductor, and a capacitor unit defined by facing the aforementioned plurality of inner electrodes for the capacitor interposing the ceramic layer are integrated. Therefore, an integrated LC component is achieved according to the present invention.
In a specific aspect according to the fifth preferred embodiment, a magnetic ceramic is used as the ceramic layer used in the aforementioned electrode green sheet defining the inductor, and a dielectric ceramic is used as the ceramic layer used in the aforementioned electrode green sheet defining the capacitor.
In another specific aspect according to the first to fifth preferred embodiments, in the process for obtaining the aforementioned laminate, at least a layer of plain ceramic green sheet prepared separately by a sheet manufacturing method is laminated on the outermost layer.
According to a sixth preferred embodiment of the present invention, a laminated ceramic electronic component using a ceramic sintered body obtained by integrally firing a plurality of ceramic layers together with an inner electrode including a ceramic sintered body and an inner electrode disposed in the aforementioned ceramic sintered body, wherein the aforementioned inner electrode has a thickness matching the entirety of the aforementioned plural ceramic layers, is provided.
In a specific aspect of the laminated ceramic electronic component according to the sixth preferred embodiment, plural inner electrodes are provided and electrically connected in the ceramic sintered body.
In another specific aspect of the laminated ceramic electronic component according to the sixth preferred embodiment, the aforementioned plural inner electrodes are electrically connected via a connection inner electrode.
In another specific aspect of the laminated ceramic electronic component according to the sixth preferred embodiment, when the width and the thickness of the aforementioned inner electrode are W and T, respectively, the ratio T/W is approximately 0.2 or more.
Other features, elements, characteristics and advantages of the present invention will become more apparent from the detailed description of preferred embodiments thereof with reference to the drawings.